Every so often it's good to exercise your brain with a math problem or two that forces you to recall principles you learned decades prior. As elementary as it might feel, you'd be surprised how easy ...

A scientific calculator has two 'log' buttons on it. These are marked log and ln. The log key is used for calculations of the form \({\log _{10}}x\). For example, to work out that \(\log 10000 = 4\) ...